1. Field of the Invention
This invention relates to impregnant compositions for porous substrates prepared from dicyclopentenyl and dicyclopentenyloxy(C.sub.1 -C.sub.4)alkyl acrylates and methacrylates and which include at least about 4% by weight of the impregnant composition of a compound selected from the drying oil fatty acids and mixtures thereof.
2. Brief Description of the Prior Art
Materials which have porous surfaces, such as concrete, stone masonry and brick, are frequently employed in applications which expose those surfaces to the weather. Although these materials have very good exterior durability in comparison with many other construction materials, there are many applications in which it is desirable to protect the exposed surface with a coating or sealer composition. For example, bridge decks are often made using concrete reinforced with steel. During the winter a bridge deck may be exposed to road salt, which while necessary to avoid dangerous icing on the bridge deck, may penetrate through the concrete to the steel reinforcing bars and thereby promote the rapid deterioration of the structure. Similarly, over an extended period the surfaces of steel reinforced concrete and limestone structures such as buildings may suffer from the penetration of water from precipitation, particularly from acid rain. Porous concrete or masonry residential foundations will often permit moisture to enter residential basements, thereby reducing the variety of uses for which these areas are appropriate. Concrete floors in a wide variety of manufacturing facilities are subject to the effects of industrial chemicals. In each of the situations, and in many others, it is beneficial to impregnate the surface with a monomer composition which will cure, or polymerize, in situ to protect the substrate from fluid penetration.
Impregnant compositions for porous surfaces based on dicyclopentenyl acrylate or methacrylate or mixtures thereof are known to be polymerizable to provide hardened, hydrophobic, abrasion resistant and impact resistant surfaces on all sorts of materials, especially on floor materials or formations whether occurring naturally or artificially produced. In the description hereinafter, the abbreviation DCP(M)A is intended as a generic term to represent one or the other, or a mixture thereof, of esters of the following formula ##STR1## wherein R is H or CH.sub.3. The (meth)acryloxy substituent may be on either the five or six position of the six member ring, and commercial products may be a mixture of the two isomers. The respective acrylate or methacrylate of the above formula may also be called: 3a,4,5,6,7,7a-hexahydro-4,7-methanoindenyl acrylate-5-(or 6) or methacrylate-5(or 6). U.S. Pat. No. 4,263,372 discloses the use of DCP(M)A in impregnant compositions for porous surfaces as well as in the formulation of polymer concrete which incorporates aggregate such as sand, marble chips, pebbles, crushed stone, and the like. This patent further discloses that DCP(M)A compositions are extremely hard when cured and that when it is desired to render such compositions more flexible, the DCP(M)A may be used with auxiliary acrylate and/or vinyl ester binder materials which can reduce the hardness and impart a more flexible or resilient character to the final compositions. Examples of such auxiliary binder materials include the (C.sub.12 -C.sub.30)alkyl or (C.sub.12 -C.sub.30)alkenyl acrylates or methacrylates, long-chain (C.sub.12 -C.sub.30)aliphatic acid vinyl esters and the di(C.sub.1 -C.sub.8)alkyl esters of maleic acid, fumaric acid or itaconic acid. The proportion of these auxiliary monomers may be from about 1/2% to 60% by weight of the DCP(M)A component, but preferably not over about 40% by weight of such component.
U.S. Pat. No. 4,097,677 discloses unsaturated esters of glycol monodicylopentenyl ethers, also known as dicyclopentenyloxy(C.sub.2 -C.sub.6)alkyl acrylates and methacrylates. These monomers may be represented by the following general formula: ##STR2## wherein R represents H or CH.sub.3 and R.sup.1 represents the hydrocarbon residue of a (C.sub.2 -C.sub.6)diol. The ester-ether chain may be connected to either the 5-position or the 6-position of the ring nucleus as indicated in the general formula. In fact, a commercial product may comprise a mixture of the two compounds in which some of the molecules have their ester-ether chain substituted in the 5-position and some in the 6-position. The expression DCPOA(M)A will be used hereinafter to generically denote any of the these monomers or a mixture thereof. In comparison with DCP(M)A, which has a characteristic, pervasive, persistant and objectionable odor under certain conditions when put into use by certain operative personnel and which when used in coating, impregnating and/or molding compositions, tends to produce extremely hard and brittle products which may require plasticizers, DCPOA(M)A is less volatile, virtually free of odor, and yields polymers characterized by a lower glass transition temperature (T.sub.g) than that which characterizes similar compositions prepared using DCP(M)A, greatly reducing or eliminating the need for a plasticizer in these compositions.
U.S. Pat. No. 4,299,761 discloses polymer concrete compositions prepared from dicyclopentenyloxyethyl acrylate or methacrylate, or mixtures thereof, hereinafter generically denoted by DCPOE(M)A. DCPOE(M)A polymer concrete compositions are generally hard and tough when cured. When it is desired to render these compositions more flexible, a small proportion of a drying oil or an acrylic polymer having a low glass transition temperature, or a mixture of a drying oil and a low T.sub.g acrylic polymer may be added to the composition and may replace part of the dicyclopentenyloxyethyl acrylate or methacrylate component. In the alternative, the dicyclopentenyloxyethyl acrylate or methacrylate may be used with a small proportion of an auxiliary liquid monomeric acrylic and/or vinyl ester binder forming material which is of low volatility and which can reduce the hardness and impart a more flexible or resilient character to the final composition. A mixture of the drying oil and an auxiliary monomer may also be used. Such other acrylic ester monomers include (C.sub.12 -C.sub.30)alkyl or (C.sub.12 -C.sub.30)alkenyl acrylates and methacrylates, (C.sub.12 -C.sub.30)aliphatic acid vinyl esters, and the di(C.sub.4 -C.sub.8)alkyl esters of maleic acid, fumaric acid, or itaconic acid. The proportion of these auxiliary monomers may be from about 1/2% to 25% by weight of the DCPOE(M)A component, but preferably is not over about 15% by weight of such component.
U.S. Pat. No. 4,400,413 discloses polymer concrete compositions having a non-volatile binder monomer system which contains from about 25% to 75% by weight based on total monomers of at least one dicyclopentenyloxyalkyl ester of a polymerizable alpha, beta-ethylenically unsaturated monocarboxylic acid selected from methacrylic acid or acrylic acid, including DCPOA(M)A, and from about 75% to 25% by weight based on total of monomers of at least one hydroxy (C.sub.1 -C.sub.6)alkyl or (C.sub.3 -C.sub.6)cycloalkyl methacrylate. These polymer concrete compositions are disclosed to exhibit improved chemical resistance in comparison with polymer concrete compositions prepared with DCPOA(M)A in the absence of the hydroxy-functional monomer. As in the case of the polymer concrete compositions prepared using dicyclopentenyloxyethyl acrylates and methacrylates, these compositions are generally hard and tough when cured. They may similarly be flexibilized by the addition of a small proportion of drying oil or acrylic polymer having a low glass transition temperature, or in the alternative, by the addition of auxiliary acrylic and/or vinyl ester binder forming monomers which have low volatility, such as the (C.sub.12 -C.sub.30)alkyl or (C.sub.12 -C.sub.30)alkenyl acrylates or methacrylates, (C.sub.12 -C.sub.30)aliphatic acid vinyl esters, and the di(C.sub.4 -C.sub.8)alkyl esters of maleic acid, fumaric acid, or itaconic acid. Similarly, mixtures of the auxiliary monomer and a drying oil may be used. The proportion of auxiliary monomer, if used, may be from about 1/2% to 25% by weight of the binder monomer system component, but preferably is not over by 20% by weight of such component.
U.S. Pat. No. 4,460,625, discloses that impregnant compositions for porous surfaces may be based upon the same monomer system.
U.S. Pat. No. 4,341,673 discloses an improved methacrylate liquid mixture for use in making methacrylate polymer concrete. "Methacrylate polymer concrete" denotes a mixture of aggregate and methacrylate monomer which is subsequently polymerized in situ, the methacrylate monomer being methyl methacrylate, ethyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate and mixtures thereof. The improvement consists of including in the methacrylate liquid mixture:
(a) 5-12% by weight of the liquid mixture of a paraffinic oil, which contains at least 60% by weight of saturated aliphatic hydrocarbons and has a boiling point above 200.degree. C. and PA1 (b) 4-10% by weight of the liquid mixture of an acrylic polymer wherein at least 90% by weight of the units of the acrylic polymer are derived from (C.sub.2 -C.sub.4)alkyl methacrylate.
The methacrylate polymer is included in the mixture in the form of minute spherical beads or crushed cubes and functions by swelling when it comes into contact with the methacrylate monomer to seal off the surface of the methacrylate polymer concrete once it has been placed into a concrete repair area, thereby reducing the loss of methacrylate monomer due to its volatility.
The impregnation of concrete using methyl methacrylate has been widely studied. Development work has been carried out to demonstrate benefits from impregnation followed by cure. Heat pretreatment of the concrete is required to obtain the desired penetration by MMA, and a heat-activated cure step is usually used following penetration. This procedure is beneficial in improving concrete abrasion resistance for severe environments such as dam spillways. However, the heat pretreatment and cure may prove impractical under conditions encountered in the field.